1. Field of Invention
This invention is directed to systems and methods for printing with substances including ultraviolet photosensitive resins.
2. Description of Related Art
Direct marking print technologies are often limited by the time necessary to dry or cure the particular material that is being printed. For example, the ink drying inadequacies associated with ink jet-type printing have resulted in a limited number of applications for printing by this method. Printing by this method is seen most frequently in slow desktop printers. Once a water-based substance used in printing is applied to a substrate, such as paper, the ink remains wet until air dried or heat dried. In applications where double-side printing is required, or where printing is performed on non-absorbent substrates, the slow dry time and paper cockling are obstacles to high print speeds. Slow dry time also limits speed and quality when printing with several different substances. For example, when different colored inks are deposited adjacent to each other, lateral, or intercolor bleed of the wet ink can reduce precision in graphics printing and other color printing applications.
A new printing technology exists that increases printing speed with fast, controllable drying ultraviolet photosensitive resin-containing substances. The ultraviolet photosensitive resins in each substance cross-link when irradiated with ultraviolet light, thus reducing the need to evaporate solvents, such as water, from the substance to achieve a solid state. Fast drying substances containing ultraviolet photosensitive resins work well with direct marking print technology near room temperature.
The lithography industry is rapidly switching over to ultraviolet curable inks and pastes to take advantage of the fast drying nature of ultraviolet photosensitive inks on various substrates. However, the ultraviolet photosensitive substances used in lithography presses tend to have high tack or viscosity. Such formulations will not work with conventional ink jet technology. To use ultraviolet photosensitive inks in inkjet printing, an ink formulation having a low viscosity is required. Such formulations are known to those skilled in the art and can be manufactured using ultraviolet photosensitive resins typically used in the liquid crystal display industry.
With direct marking print technologies, such as ink jet applications, drop diameter spread control directly impacts the quality of print image resolution. To minimize lateral ink spread, the drop volume needs to be controlled and minimized, generally by using various ink delivery technologies. Properly selecting the target media substrate is also important. For example, cut-sheet paper tends to absorb water-based ink vertically and laterally, i.e., into and along the surface of the sheet. Furthermore, for printing on non-absorbing and semi-absorbing substrates, like transparencies, slow drying liquids, such as water based inks, will stay fluid and be held by surface tension until dried. These undried liquid puddles tend to smear if touched before they are completely dried.
In direct marking ejection or deposition methods, such as inkjet printing, the properties of the substances being ejected or deposited are beneficially different at different stages of the process. For example, in the ejection head of a fluid ejection system, low viscosity is desirable, so that the fluid, such as ink, can be readily deposited on a substrate. For a brief time after an ejected fluid droplet hits the substrate, a medium viscosity is desirable to allow intimate bonding of the fluid to the substrate, such as ink to the fibers of a sheet of paper, in a controlled fashion. However, quickly thereafter it is desirable that the fluid becomes rigid, to avoid lateral bleed and further vertical penetration, which can cause paper cockling. Curing substances containing ultraviolet photosensitive resins with conventional ultraviolet illumination, such as with a lamp or electron beam, makes it difficult to obtain the two separate viscosity phases of the substance that follow deposit on a substrate as described above.
Uncontrolled lateral spread of ejected fluids used in fluid ejection systems can be reduced and controlled by using fluids containing ultraviolet photosensitive resins. The quick-drying nature of such fluids eliminates the problems of uncontrolled lateral spread and slow drying of ejected fluids. Due to the fast-drying nature of fluids containing these resins, such as ultraviolet photosensitive resin ink, this fluid ejecting method is extendible to ejecting fluids onto any substrate. Ultraviolet light intensity and exposure time duration can provide control over lateral spread, by permitting the partial curing of a fluid containing an ultraviolet photosensitive resin.
Curing fluids or other substances, such as inks, containing ultraviolet photosensitive resins, is often accomplished using an electron beam or an ultraviolet lamp. Such methods of curing an ultraviolet photosensitive resin are deficient, because, for example, the ultraviolet lamp emits broad ranges of frequencies and wavelengths of ultraviolet light, and can not be used to selectively cure multiple ultraviolet photosensitive resins, that react to certain specific target wavelengths of ultraviolet light. Such methods also waste energy, by emitting light at wavelengths that are not absorbed by the employed resins. Such methods are also limited in their applications, due to considerations of portability, power consumption, and ability to achieve a small form factor.
Thus, there is a need for an improved method of curing substances containing ultraviolet photosensitive resins.
This invention provides systems and methods for curing substances containing ultraviolet photosensitive resins using ultraviolet light emitting devices.
This invention provides systems and methods for curing substances containing ultraviolet photosensitive resins that provide enhanced portability, power consumption, and the ability to achieve a smaller form factor.
This invention provides systems and methods for curing substances containing ultraviolet photosensitive resins that permit irradiation with narrow ranges of wavelengths of ultraviolet light, and selective irradiation of multiple substances that are sensitive to distinct wavelengths of ultraviolet light.
Various exemplary embodiments of the methods according to this invention include depositing or ejecting at least one substance that includes an ultraviolet photosensitive resin on to a substrate, partially curing the substance by irradiating the substance with at least one ultraviolet light emitting device, and subsequently completely curing the substance.
Various exemplary embodiments of the systems according to this invention include an applicator usable to eject or deposit at least one substance that includes an ultraviolet photosensitive resin onto a substrate, and at least one ultraviolet light emitting device or at least one array of ultraviolet light emitting devices, positioned relative to the applicator, and capable of irradiating the at least one substance that has been ejected or deposited onto the substrate.
Various other exemplary embodiments of the systems according to this invention include an intermediate substrate, an applicator usable to eject or deposit at least one substance that include an ultraviolet photosensitive resin onto the intermediate substrate, a first ultraviolet light emitting device positioned relative to the intermediate substrate usable to partially cure the at least one substance on the intermediate substrate. The intermediate substrate is positioned to be usable to transfer the at least one substance from the intermediate substrate to a second substrate.
These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention.